LAUSR

Abstract We report on thermoelectric properties of low Ge content n -type Si 0.9 Ge 0.1 –Mg 2 Si nanocomposite. Introduction of the Mg 2 Si phase into a SiGe matrix resulted in a dramatic drop of the lattice thermal conductivity beyond the previously reported lowest limit for SiGe alloys due to intensification of phonon scattering on SiGe–Mg 2 Si grain boundaries. For a sample doped with 1 at.% of Mg 2 Si, the peak value of thermoelectric figure of merit ZT reached ~ 0.8 at 800 °C. Sintered nanocomposites still exhibit high thermoelectric performance while being almost two times cheaper than Si 0.8 Ge 0.2 .